Store election piston with gas return



April 5, 1960 H. M. MEADOWS ETAI- 2,931,341

STORE EJECTION PISTON 111m GAS RETURN 4 sheets-Sheet 1 Filed Jan. 7, 1957 INVENTORS HARRY M MEADOWS JOHN c. STEINMETZ lailw 11 ATTORNEY April 5, 1960 H. M. MEADOWS ETAI- 2,931,341

STORE EJECTION PISTON WITH GAS RETURN Filed Jan. 7, 1957 4 Sheets-Sheet 2 INVENTORS HARRY M. MEADOWS JOHN G. STEINMETZ 2422 raw ATTORNEY April 5, 1960 H. M. MEADOWS EI'AL 2,931,341

STORE EJECTION PISTON wm-z GAS RETURN 4 Sheets-Sheet 3 Filed Jan. 7, 1957 ATTORNEY Apqil 5, 1960 H. M. MEADOWS ETAL 2,931,341

STORE EJECTION PISTON wrm GAS RETURN Filed Jan. 7, 1957 4 Sheets-Sheet 4 FIG.8

INVENTORS HARRY M. MEADOWS JOHN C. STEINMETZ ATTORNEY sroan nsncrroN PrsroN wrrn GAS RETURN Harry M. Meadows, Granada Hilts, and John C. Steinmetz, Anaheim, Calif., assignors to North American Aviation, Inc.

Application January 7, 1957, Serial No. 632,915

6 Claims. (Cl. 12138) This invention pertains to a store suspension and release device and more particularly it relates to an extendible device for forcibly ejecting an attached store wherein the ejecting device is automatically returned to its retracted, store-suspending position upon ejection of the store.

The gas-return telescopic ejecting pistons of the present invention constitute an improvement and an advance in the art over the spring-return pistons incorporated in and forming a part of the store ejector disclosed in Patent No. 2,822,207 and assigned to North American Aviation, Inc., the assignee of the present application.

The occurrence of spring failures in the standard type of spring-returned pistons has resulted in inability to raise the pistons into a retracted position after firing of the ejector mechanism and release of the store. The extended ejection pistons cause an increase in drag on high speed aircraft which cannot be tolerated due to the significant loss in speed and range resulting therefrom.

These and other objections and disadvantages of the prior type of spring-return pistons have been overcome and eliminated by the present gas-operated construction for retraction of the extendible ejector pistons. The present invention contemplates a plurality of hollow, telescoping, concentric pistons within a cylinder, each piston having a head portion that can be acted on by pressurized gases in a direction to retract the pistons within the cylinder as well as extend the pistons therefrom, and a means for applying pressurized gases to said pistons to first extend and then to retract them. More specifically it provides a gas pressure storage chamber that is placed in communication with the pressurized gases in the interior of the cylinder after a predetermined amount of piston stroke and which successively communicates with the spaces under the aforementioned piston head portions, and italso provides a means for releasing the gas pressure within the hollow pistons after ejection of the store whereby the pistons will be successively retracted by the pressurized gases acting against the under surfaces of the piston head portions.

Accordingly it is an object of this invention to provide an automatic, positive-acting piston type store ejector that automatically retracts after release and ejection of the store.

t is also an object of this invention to provide a gasactuated piston type store ejector that is not dependent upon mechanical means for retraction.

' It is a further object of this invention to increase the dependability and operability of the store ejectors pres ently in use.

It is also an object of this invention to replace the conventional spring-return type of ejection pistons by an automatic gaspressure-operated return and thereby reduce reduce maintenance as well as operational hazards.

These and other objects and advantages of this invention will become more apparent when read in the light of the accompanying drawings and specifications wherein:

Fig. .1 is an installational view showing the relation of the gas-operated ejector and piston return of this Patent 2,931,341 i atented Apr. 5, 1960 porting element and carries a store suspended therefrom.

Fig. 2 is a longitudinal sectional view of the device of this invention showing the cylinder and the telescopic pistons retracted therein and also showing the stored supporting hook in a latched position but without a store suspended therefrom.

Fig. 3 is a longitudinal cross-sectional view of the device of this invention showing the telescopic pistons fully extended from the cylinder in a store ejecting position.

Fig. 4 is a longitudinal cross-sectional view of the inven tion showing the telescopic pistons partially retracted.

Fig. 5 is a top plan view of the cylinder block of this invention.

Fig. 6 is a cross-sectional view of the cylinder block of this invention taken in the plane of line 66 in Fig. 5, fragmentarily showing the pistons nearly fully extended and showing the gas-return conduits communicating to the space under the outer piston head.

Fig. 7 is. a sectional view of the cylinder body taken in the plane of line 7--7 in Fig. 5, showing the gasreservoir intake port covered by the outer piston and showing the gas-return system intake check valve.

Fig. 8 is an enlarged cross-sectional view of the upper portion of the check valve mechanism shown in Fig. 7.

Fig. 9 is a transverse cross-sectional view of the cylinder block and pistons taken in the plane of line 9-9 in Fig. 2, and showing the gas-return system accumulator chamber.

Fig. 10 is a transverse cross-sectional view of the cylinder block and pistons taken in the plane of line 10-10 in Fig. 2 with the relief'valve omitted and showing the relationship of the gas inlet apertures at the bottom of each piston to the gas inlet conduit as well as showing the residual gas bleed-off conduits.

Referring specifically to the drawings wherein like reference characters have been used throughout the several views to designate like parts and referring at first to Fig. 1, reference numeral 1 generally designates the suspension and ejection device of which the gas-retracted ejectionpistons of the present disclosure form a part. The suspension and ejection device 1 is enclosed in a streamlined pylon 68 and supports a store 69, such as a bomb or fuel tank, from a wing or fuselagesurface 70 of an aircraft. As best shown in Figs. 2-4, the extendible and retractible piston ejector device 2 of the present invention comprises a cylinder block 3 having a cylinder bore 4 extending longitudinally therethrough. The upper end of the cylinder bore 4 is internally threaded to receive a threaded cylinder closure member 5 having an overlapping flanged portion 39 and a central hexagonal head portion 6 permitting easy installation and removal with a wrench. Closure member 5 includes a depending axially eccentric annular portion 71 of a variable wall thickness which provides a stop for limiting the upward travel of pistons 8 and 17. A chamber 38 is formed in one edge of annular portion 71 and provides initial access by the gases to at least a portion of the upper surfaces of piston heads.

extendible pistons nested One within the other and all.

positioned within the cylinder, bore 4 when retracted; Outer concentrlc piston 8 is slidably positioned-within cylinder bore 4 and has an annular outwardlyextendin'g;

hold the pistons in their retracted position. 7 end of piston 17 is closed by an'etid wall 20 having an against pressure loss and leakage.- The bottom end of;

piston. 8 is generally closed by'an end wall 12 centrally apertured at 13 for the passage of the inner coaxial piston 17 with aperture 13 having a suitable O ring sealing means l6 foirtallowing; sliding movement of inner piston 17 relative to piston 8. An annular recess 11.is formedv in. the inner surface of the piston wall at the bottom of under the annular head portion 18 of piston 17.- An.

ring 15 is positioned in an annular groove in the-reduced diameter lower portion 76 at the bottom of cylinder bore' 4 to allow reciprocal movement of piston Swithout leakage or pressure:.loss therefrom. Coaxial 'inner hollow piston 17 is formed with an annular flanged piston headv portion 18 similar in construction to that of piston 8 and' having annular expansion r'ings 19 positioned in grooves in head portion 18 to provide a seal between the two pistons. pansion rings and the sealing 0 rings are sufiicient to The lower axially oifsettlongitudinal opening 21 therethrough. In addition a plurality of equally spaced radially disposed circular openings,j23 connect the lower end of theinterior ofhollow piston 17 with annular recess 11. it will be 'noted that the annular, flanged head portions of the pistons in conjunction with the piston and cylinder walls form annular chambers separating the individual pistons and the cylinder. wall. an annular internal flange 24 on the inner surface ofpiston 17 forms an exhaust gas chamber 31 in the lower end of piston 17, with access into the chamber a being provided by relief valve 25. This chamber is sealed from'the interior of the pistons and-cylinder'when the. relief valve 25 is. held in-its uppermost position by the store but upon ejection of the store the valve ismoved downwardly by the gas pressure within the pistons in a manner to place the interior of the pistons in communication with the exhaust chamber 31. r

The radial pressures exerted by the piston exthrough end wall 20 and integral depending lug 22, to atmosphere. 'These conduits 66 provide a further means for relieving any gas pressure within exhaust chamber 31, since they communicate directly with chamber 31 when valve 25 is in a raised position and indirectly by means of slot 73 when valve 25 is bottomed on end wall 20, as in Figs. 3 and 4. .A pin 74 is positioned in a diametral bore in the closed end 29 of the valve body.

' piston 8 to assist in distributing the gas pressure evenly Spaced a short distance above end.

' 14, 11 and the exhaust chamber 31 when the pistons are Relief valve 25 performs the function of relieving the residual gas back pressure-within the pistons and cylinder so that the pistons may be retracted. It generally comprises a hollow cylindrical valve body 26 having an-end wall 29 closing the lower end thereof and an annular radial outwardly extending flange 27 at the upper end 7 thereof for slidingcontact with the interior of piston 17. Apertures' 28 are circumferentiallyspaced in the wall of cylinder 26 and are, positioned a predetermined distance above the end wall'29 so that when relief valve 25 is held in its uppermost position apertures 28 are above flange 24 or at most are in juxtaposition thereto and the interior of the pistons and cylinder are not in communi-' cation with chamber 31. A valve body finger 30 de-' pends fromthe lower end of the valve 25 and extends through aperture 21 for contacting the store'suspending When thus held in its upper" position by lug 67,'valve 25 is in a closed attitude and lug 67 as shown in Fig; 1.

the exhaust chamber 31 is not in communication with the: interior of the piston and cylinder assembly. Upon V ejection of the store the valve is no longer restrained and is free. to move downwardly under the pressure of the residualgases in the cylinder and piston, and the interior of the pistons and. cylinder are thus. placed in communication with chamber 31. Aslshown in Figs-sand 4 when the pistons are inan extended position and the store has. been ejected chamber 31 is then in communicatlon with.

the ambient atmosphere through the apertures 23 and thus the residual. gas pressure within the pistons. and cylinder maybe exhausted. to theatmosphere. The bottom surface. ofthe relief valve endv wall 29: contains a slot 73: extending chordwise therethrough' and communicatingat; eachtendwith chamber 31. Directly below slot 'lit-qtwo. bleed-cit conduits 66 extend longitudinally in a retracted position. The gasreturn system retracts the ejector pistons by means of the residual gas pressure remaining in the sys' tion.

The ends of this pin project .sufli'ciently therefrom to contact annular flange 24 in the upper closed position'i the V-shaped groove 34in the depending cylinder wall to properly align piston 17 relative to the store lug and hook 35. The stud 33 also'secures a strike plate .75 to lug 22 in alignm'entwith the lower edge of piston 8.,

Upon downward movement of piston 8 this lower edge contacts plate 75 and carries piston 17 down with it. This insures that piston 8 does not act on the store lug 67 to separate it from finger 30 and thereby allow release of the gas pressure before inner piston 17 has been'fully extended. Thus-pistons 8 and 17 move downwardly as a. unit until piston 8 bottoms on portion 76 of cylinder bore 4 while piston 17 continues to move downwardly to its fully extended position. I

Radially spaced in the bottom portion of the wall of piston 8 are apertures 36 connecting annularrecess 11 in piston wall 8 with an annular recess 14 formed. in the inner wall ofthe' cylinder bore 4'. Apertures 36 are so positioned with respect to end wall12 of the piston that" they form grooves in the upper surface of the end wall. Thus, when piston head 18. abuts end wall 12 in the extended position, gas pressure may be exerted under the piston head 18 by means of the grooves in a manner to raise piston 17., It will be noted that apertures 36 and 23 in pistons 8 and 17 respectively are in'registry with and allow communication between the annular recesses tent near the end of the power stroke. It comprises generally a gas pressure storage means and a conduit'sys'-' tem for applying the gas pressure. under thevannular 'flanged piston heads ina manner to retract the extended More specifically the residual gas within the" pistons. downwardly moving pistons is' at a sufiiciently high pressure to open check valve 41 and flow into the accumulator or reservoir chamber 42 when the pistons have moved downwardly and uncovered port 43 in the side of bore 4; Asthe pressure within the cylinder and pistons drops below the pressure in the reservoir upon operation of relief valve 25, check'valve 41 closes, retaining high pressure gas in reservoir chamber 42 and the conduits connectedthereto. f 7

As shown in Fig- 6, reservoir chamber 42 coinmtini cates through port 57with conduit 53' and thence through conduits 59 and 62 with annular recess 14 in the cylinder wall. It will be noted that conduit 62 forms a groove in the lower surface or" recess 14. This allows. the high pressure gas'to act under piston head 9 of pi'ston'Swhehthe piston is in its outermostextended orbottomed posiconduits are formed-by drilled intersecting bore holes having their outer ends threaded forthe reception of closure members 60, 61 and'63. in conduits58, 59'and' 62' respectively; a v r V s i Check valve 41 comprises a'valve body 47' seated on theshoulder 46 formed between. valve; chamber 44' and reduced diameter inlet chamber 45 which. connects. to in.--

'let port 43in the cylinder wall' 4. .Valvestem. 48. ex

tends axially through valve bore 44 andhas an enlarged head portion 49 at itszupper end. Aspringjtl'is seated It will be'noted that for lease of 'constructi'on the in a retainer cup 51 and bears against the head portion 49 to bias valve 47 to a closed position. Valve guides 55 near the top and bottom of valve stem 48 insure axial movement of the valve and valve stem without cocking. Valve bore 44 connects through port 56 into reservoir chamber 42 for the storage of gases.

. As best shown in Fig. 8, the closed upper end of spring retainer cup 51 has an integral axially extending threaded stem 37. A washer 52 is located in an enlarged counterbore 7'7 at the upper end of valve bore 44 on stem 37 with a seal 53 located on the washer 52 to prevent escape of the gas through the counterbore. This whole assembly is held in position by a nut detent 54 threadedly engaging the upper end of stem 37. Detent 54 bears against the undersurface of a cut-out portion 72 formed in the undersurface of flange 39 of the closure This undercut portion 72 has a hemi-cylindrical configuration and is so disposed in the closure member that it is positioned over the detent 54 and partially covers the same when closure 5 is threaded into cylinder block 3 to its fullest extent to close the bore 4. Since retainer cup 51, washer 52, seal 53 and detent 54 are biased in an up- Ward direction by spring 50, detent 54 is moved upwardly into undercut portion '72 thereby locking closure 5 against rotation. Ready installation and removal of closure 5 may be accomplished by simply depressing detent 54 to a position below or flush with the top of block 3, by means of pressure on its exposed outer edge, thereby allowing closure member 5 to be threaded into or out of engagement with block 3. It will be noted that the counter-bore 77 is of a sufficient depth to allow axial movement of the detent assembly to permit ready unlocking of the detent.

Cylinder block 3 may be suitably connected to suspension device 1 by means of bolts or other suitable fasteners engaging the cylinder block through the transverse fastener apertures 64 and 65.

The gas pressure for operation of the ejection and retraction mechanism may be secured from stored pressurized gases or as set forth in Patent No. 2,822,207 it may be generated by the combustion of a suitable powder charge in a breech block.

In operation, therefore, upon release of the hook locking mechanism 35 as taught in Patent No. 2,822,207 the gas pressure is applied through conduit 7 to the heads of pistons 8 and 17 to extend them to their outermost positions as shown in Fig. 3. The power stroke of the telescopic pistons forcibly ejects the store away from the aircraft. Upon movement of the store away from the lower end of piston 17 the finger Si) is no longer restrained against downward movement by store lug 67. The gas pressure thereupon forces the release valve into its lowermost position and places the interior of the hollow pistons and cylinder in communication with exhaust chamber 31 through apertures 28. The residual gas pressure within the pistons can then exhaust to atmosphere through apertures 23 in the piston.

As the pistons move downwardly gas intake port 43 is uncovered and the residual gas pressure in the cylinders overcomes the force of spring 50 to open valve 47 and pressurize reservoir chamber 42. From chamber 42 the gas flows through conduits 58, 59 and 62 into annular recess 14 to act under the head portion 9 of cylinder 8 and thereby raise the same. It will be noted that there is nothing to prevent the flow of gas to the space under the head portion of piston 8 once the gas begins to enter the reservoir chamber 42. This tends to cushion the piston head at the bottom of its downward stroke and prevent abrupt contact of piston head 9 with the bottom surface of annular recess 14. With release of the residual gas pressure from the cylinder and piston interiors by means of valve 25, the pressurized gas retained in the accumulator and associated conduits by check valve 47 acts under the head 9 to raise piston 8 into its retracted position, as shown in Fig. 4. This brings aperture 36 in the lower portion of piston 8 into registry with the an nular recess 14 and thereby permits the pressurized gas to flow into annular recess 11 in piston 3 and under head 18 of piston 17 thereby retracting piston 17 to its uppermost position against stop portion 71. Upon complete retraction of piston 17 apertures 36 and 23 are in registry,

as shown in Fig. 2, and the residual gases within the gas return system may then exhaust to atmosphere through slot 73 and bleed conduits 66.

It is a feature of this invention that the relief valve 25 permits the ejector to be fired without having a store loaded thereon, without damage to the ejector. If the ejector should be inadvertently fired without a store suspended thereon the relief valve would have nothing to react against and, accordingly, would not be maintained in its retracted position but would immediately be forced downwardly so as to uncover apertures 28, if the valve was not initially in its lower, open position. This would allow all of the explosive gases to escape without reacting against pistons 8 and 17 so that there wouldbe no damage to these pistons by means of their being forced violently to the limits of their travel.

It will thus be seen that by the present invention we have provided a reliable, improved, positive-acting piston return means for an aircraft stores-ejector which is not dependent upon any mechanical type return means, such as a spring, which in the past have been subject to malfunctioning and failure due to the high pressures and forces acting thereon.

While a particular embodiment of this inventionhasl been illustrated and described herein, it willv be apparent that various changes and modifications may be'jrnade in the construction and arrangement of the various parts without departing from the spirit and scope of this invention in its broader aspects or as defined in the fol-;

lowing claims.

We claim: 1. In a gas-operated device adapted to be carried by an aircraft for forcibly ejecting a store which has means thereon for releasable attachment to said device comprising in combination, a latch means for releasably securing the store, a source of pressurized fluid, a body having a cylindrical bore open at one end and closed at the piston, said pistons being extendable to forcibly eject the store when acted on by the pressurized gas, reservoir. means communicating with the cylindrical bore intermedi ate its ends operable to store a portion of the pressurized gas therein after a predetermined amount of extension of the pistons, means for releasing the gas pressure within said bore and hollow pistons upon ejection of said store,

and conduit means for successively applying the reservoir gases under the annular head of the first piston and then under the annular head of the second piston to succes;

sively retract the said pistons.

2. An apparatus adapted to be carried by an aircraft for forcibly ejecting a store which has means thereon for I releasable attachment to said apparatus comprising in combination, a latch means for releasably securing the store; a source of pressurized fluid; a cylinder means: communicating directly with the source of pressurized fluid; a plurality of hollow concentric pistons slidably positioned within said cylinder and telescopically ex tendable therefrom, each of said pistons having opposed pressure surfaces thereon; one of said pistons having a portion contacting the store attaching means adapted *to release :the latch and forcibly eject the store when said pistons are extended by the application of the presurized "fluid to one of said surfaces of the said pistons; means operatively contacting the store attaching means and operable thereby upon extension of said pistons and ejection of the store to release the internal fluid pressure in said hollow pistons and said cylinder; means communicating with said cylinder for withdrawing and storing pressurized fluid from within said cylinder after a predetermined amount of travel of said pistons; means for automatically applying said stored pressurized fluid upon substantially full extension of the said pistons first to'the other of said surfaces of one of said pistons and then to the other of said surfaces of the other of said reeiprocable inner and outer telescoping pistons means,

in ;saic l chamber operatively contacting the store attachment means and extendible outwardly from said chamber upon the application of pressurized {fluid thereto whereby thelatch is released and the store may before ibly ejected; areservoir communicating with said cham- 8 1 tion, said first piston having apertures "therethrough near its lower end whereby upon retraction of said 'firstpiston communication is effected between'said reservoir and the underside of'said second piston to retract said second pistonJ 5. An apparatus adapted to be carried by an aircraft for forcibly ejecting a store which has means thereon for releasable attachment to said apparatus comprising in combination, a latch means for releasably securing the store; a source of pressurized fluid; a cylindercommunieating directly with the source of pressurized fluid; a first hollow piston reciprocable in said cylinder and including'apertures in the piston wall surface'thereof at its lower end; a second hollow piston reciprocable within said first hollow piston and forming with said first piston wall apertures a slide valve, e'ach'of said pistonshaving opposes pressure surfaces thereon and being telescopi cally extendible upon the application of pressurized fluid to one of said surfaces; said second piston having an outlet at its lower end; a relief valve normally closing said lower end'outlet operable upon ejection of the store g and release of the store attaching means to open and exher intermediate said ends for storing a pertionof the,

fluid pressure, a check valve interposedbetween the res-i e 'rv.oir and said chamber preventing flow of pressurized gas back 'into said chamber upon release of the pressure within said chamber; means in said body member pro-f viding communication from said reservoir directly to the lower end of said chamber; valve means in the inner piston normally biased to closure by the store attachment means and operable upon ejection of said store and release of said store attachment means to exhaust the remainder of 'the applied pressure from said chamber; means for applying the stored portion of fluid pressure beneath said outer piston to cushion the outward movement of the same and then acting beneath first said outer piston and then said inner piston to sequentially retract first said outer piston and then said inner piston.

4. An apparatus adapted to be carried by an aircraft for forcibly ejecting a store which has means thereon for.

releasable attachment to said apparatus comprising in combination, a body having a, cylindrical bore open at one end and closed at its other end and connected at haust the fluid pressure from said cylinder and said pistons; a reservoir communicating with said cylinder intermediate its ends for storing a portion of the applied fluid pressure; port means in the cylinder wall 'at the lower end of said cylinder communicating with said reservoir whereby the stored fluid pressure portion may be applied first to the other of said pressure surfaces of the first piston to return the same to a retracted position and then sequentially by operation of said slide valve whereby the stored fluid pressure may then be applied'to.

the other of said pressure surfaces of the second piston to return the same to its retracted position.

6. A dual piston actuator operable under the action of a high pressure, short durationpulse generated by combustion of an explosive charge to sequentially extend and retract comprising a cylinder .member having its head end connected directly to the explosive charge its closed end to a source of pressurized gas; a latch I ciprocable therein and extendible therefrom, said second piston being open at its upper end and having an outletat its lower end; a 'valve normally closing said lower end outlet but operable upon ejection of the store and release of the store attaching means to open and exhaust fluid pressure from said cylindrical bore and said pistons; a reservoir communicating with said bore intermediate its ends for withdrawing and storing agpontion of the applied fluid pressure, said reservoir communicating di-' rectly'w'ith the lower end of said bore whereby'the stored fluid pressure portion may be applied beneath said first piston ,head'portion to return the same to a retracted posifiller; a first hollow open ended piston reciprocable within said cylinder and extendible therefrom and having port means intthe piston wall near its lower end providing communication from its exterior to its interior surfaces; a second hollow piston means reciprocable within said first piston .means and extendible therefrom and having an outlet at its lower end; avaive means normally closing said lower end outlet operable upon extension of the pistons to open and exhaust the gas pressure from within said cylinder and pistons; a reservoir means communieating with said cylinder intermediate its ends for storing a portion of the applied fluid pressure; port means in the lower end of said cylinder communicating with said reservoir and in alignment with said first piston portmeans upon retraction of said first piston whereby the store fluid pressure may be applied successively first beneath said first piston and then beneath said second piston through said first piston ports whereby said first and second pistons are sequentially retracted.

References Cited in the file of this patent UNlTED STATES PATENTS France Nov. 14, 1951 

